1. Field of the Invention
The present invention relates to a method for the heat treatment of metal strips such as aluminum, copper and iron strips, the method comprising heating such metal strips while being passed through a heating zone, and then cooling the strips while being passed through a cooling zone, thereby applying heat treatment such as annealing to the metal strips.
2. Description of the Prior Art
In the prior arts, in the case where a metal strip (The term "metal strip" as used herein indicates a thin and lengthy band-like metal plate continuously rolled by a rolling mill. The thickness of the metal plate is normally less than 3.5 mm, and the plate has various widths.) is subject to heat treatment as mentioned above, great thermal stresses are introduced in the strip as indicated at the dotted lines in FIG. 6 or FIG. 9, and when the thermal stress overcomes the antibuckling stress of the metal strip, it gives rise to wrinkles, in the metal strip, in parallel to the moving direction thereof. These wrinkles result in a defective metal strip.